Influenza Vaccination in Pregnancy Not Linked to Adverse Offspring Health Outcomes

Seasonal influenza vaccination during pregnancy is not significantly associated with adverse early childhood health outcomes among offspring, according to study results published in JAMA.

While seasonal influenza vaccination in pregnancy can reduce influenza illness among pregnant women and newborns, there are limited data on whether seasonal influenza vaccination in pregnancy is associated with adverse childhood health outcomes. Therefore, researchers assessed the association between maternal influenza vaccination during pregnancy and early childhood health outcomes through a retrospective cohort study using a birth registry linked with health administrative data.

All live births in Nova Scotia, Canada between October 1, 2010 and March 31, 2014 were included, with follow-up until March 31, 2016. Among 28,255 children, 10,227 (36.2%) were born to women who received seasonal influenza vaccination during pregnancy. During a mean follow-up of 3.6 years, there was no significant association between maternal influenza vaccination and childhood asthma (incidence rate, 3.0 vs 2.5 per 1000 person-years; adjusted hazard HR [HR], 1.22; 95% CI, 0.94-1.59), neoplasms (incidence rate, 0.32 vs 0.26 per 1000 person-years; adjusted HR, 1.26; 95% CI, 0.57-2.78), or sensory impairment (incidence rate, 0.80 vs 0.97 per 1000 person-years; adjusted HR, 0.82; 95% CI, 0.49-1.37).

In addition, maternal influenza vaccination in pregnancy was not significantly associated with infections in early childhood (incidence rate, 184.6 vs 179.1 per 1000 person-years; adjusted incidence rate ratio [IRR], 1.07; 95% CI, 0.99-1.15) or with urgent and inpatient health services utilization (incidence rate, 511.7 vs 477.8 per 1000 person-years; adjusted IRR, 1.05; 95% CI, 0.99-1.16).

This study has several limitations, including that some of the influenza vaccination data was based on patient self-report, which may be less reliable. In addition, outcome misclassification could not be ruled out as the majority of study outcomes had not been validated. Outcome measurement was limited to diagnoses made in emergency departments and during hospitalizations. Thus, given the observational nature of the study, the small event numbers for neoplasms, and the imprecise 95% confidence intervals around some point estimates, these results should be interpreted cautiously.

The study authors concluded, “In this population-based cohort study with mean follow-up duration of 3.6 years, maternal influenza vaccination during pregnancy was not significantly associated with an increased risk of adverse early childhood health outcomes.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Mehrabadi A, Dodds L, MacDonald NE, et al. Association of maternal influenza vaccination during pregnancy with early childhood health outcomes. JAMA. 2021;325(22):2285-2293. doi:10.1001/jama.2021.6778